Dr. Bailey-Wilson is a member of a collaborative study of Attention Deficit Hyperactivity Disorder, collaborating with Drs. Max Muenke and Kate Berg of NHGRI and Dr. Mauricio Arcos-Burgos of Columbia. Dr. Bailey-Wilson's role is to help with study design and to serve as statistical geneticist on the project. In the past, we have performed power studies of many large pedigrees from Columbia, showing that there will be adequate power in a linkage study to detect genes of moderate to large effect, even in the presence of heterogeneity. Dr. Bailey-Wilson also advises the other collaborators about the types of pedigree structures that are particularly informative for linkage studies. A paper detailing the study design and the simulation has been submitted. In this fiscal year, linkage and association studies have been performed on the first set of large pedigrees from Columbia for markers in several candidate loci. A manuscript reporting these results is in preparation.